1. Field of the Invention
The present invention relates to a method for protecting porous components subjected to large potential differences and to the components thus produced.
2. Description of the Related Art
Numerous electronic devices employing high voltages use elaborate components based on porous materials, for example ceramics. These materials can therefore absorb low-viscosity fluids by capillary action.
The overall electrical insulation of the electronic device is conventionally ensured using a dielectric fluid, for example a mineral oil; this fluid can penetrate the pores of the material. If the component is subjected to a large potential difference applied in a very short time, the dielectric fluid present in the cavities of the porous material may be partially destroyed and release conductive carbon-containing particles. The local damage can then extend and result in short-circuiting of the component, which immediately leads to its complete destruction. Another possibility of damage exists if the dielectric fluid can release gas bubbles under the effect of an electric field (the so-called "degassing" phenomenon). In this case, a gas bubble created in a microcavity can generate a high stress on the walls of the cavity and crack the material, which also leads to destruction of the component.